Preparation of substituted lower aliphatic acids



Patented on. 11, 1949 PREPARATION OF SUBSTITUTED LOWER aurna'rrc scms Huh I. Hagemeyer, In,

Eastman Kodak slgnor to K m rt, e n, sl-

Company, Rochester,

1., a corporation of New Jersey No Drawing. Application May 15, 1943,

Serial No. 670,032

3 Clslml. (Cl- 260-514) This invention relates to the preparation oi carboxylic acids and more particularly to the preparation of substituted aliphatic carboxylic acids by the reduction of p-lactones obtained from aromatic aldehydes, or aromatic ketones, and polymers of such p-lactones.

The p-lactones employed as starting materials in my invention may be prepared by condensing a ketene with. an aromatic aldehyde or an arcmatic ketone in the presence of a suitable catalyst, such as a Friedel-Crafts type catalyst, or in the presence or sodium, potassium or lithium salts of organic carboxylic acids, for example, sodium acetate at temperatures below 50 C. The use of a Friedel-Cralts catalyst in forming p-lactones is described in U. 8. Patent 2,356,459 of August22, 1944; and the reaction of ketene with iurlural and benzaldehyde in the presence of potassium acetate as the catalyst is described by C. D. Hurd, J. A. C. S. 55, 275 (1933). The reaction for preparing these ,s-lactones can be represented by the equation wherein n represents a whole number 1, 2, 3, 4, etc; B may be aromatic, e. g. phenyl or naphthyl, and cycloaliphatic, e. g. cyclohexyl, or fury]; and R" and R." may be hydrogen, methyl, ethyl, phenyl, etc.

Another objector the invention is to provide a method for the hydrogenation of p-lactones made from aromatic aldehydes and aromatic ketones,

2 and low molecular polymers 01' such p-lactones, to carboxylic acids,

Still another object is to prepare ester lactones by the hydrogenation of the addition products of ketenes with i'urfural, said ester-lactones having the following general structure:

wherein B may be hydrogen, methyl, ethyl,

. phenyl, etc.

Other objects will become apparent hereinalter.

In accordance with the invention, it has been discovered that substituted aliphatic carboxylic acids can be prepared by the hydrogenation of the fi-lactones obtained from aromatic aldehydes and aromatic ketones, and also by hydrogenation of the low molecular weight polymersoi such p-lactones, in the presence of a suitable catalyst at elevated temperatures and pressures.

The objects of the invention may thus be accomplished in accordance with one feature 01' the invention, by hydrogenating the selected fl-lactone in the presence of a catalyst, such as Raney nickel. The hydrogenation converts the lactone group to a carboxylic acid as shown in the following equation which illustrates the basic reaction of the invention.

swam-Po a'--ca'a' p-lactone MOHQMCHB'CW'IV'COOH Carboxylic acid In this equation, R, R, R" and n have the sigreference to the following examples.

Example I Ketene. was passed in through a high speed stirrer intd grams of benzaldehyde containing 0.5 gram oi anhydrous sodium acetate while maintaining a reaction temperature or 3040 C. The p-phenyl-p-propiono lactone thus produced was then placed in a stirrer type copper lined autoclave and hydrogenated using Raney nickel of ZnCh was reacted with ketene (0.48 moL/hr.)

assess? 3 catalyst at 180 C. and 700 pounds per square inch until no more hydrogen was absorbed. Distillation gave 84 grams of p-cyclohexyl propionic acid. B. P. 141', C. Np 1.4824, N. E. 155. The reaction maybe expressed by the fol- 5 trample IV 200 grams of benzaldehyde containing 0.2 gram of mm: were reactedsvith ketene at -10' C. The catalyst was washed out with 5% alkali. One

lowing equation: gram of K260: was added and the fl-phenyl-p- CHCHO cm=c=o-q I propiono lactone was heated at 80' C. for one hour under which conditions a low molecular g? M weight polymer of this lactone was formed. The in polymer mixture was placed in a small stirrer type autoclave and reduced over Raney nickel at n =0 a-oydohesyl 110 to 120 C. Distillation of the product gave 102 grams of fl-phenyl propionic acid, 3. P.1d 145 C. propionoladons Crystals were obtained upon cooling. M. P. 40

g g to 48 C. The following equation represents the reaction in which a: indicates the extent oi poly- W of 03 m'eriaation and may be a whole number:

( CaHsCH-O at 0-10 C. for 8 hours. The catalyst was neutralized with 5% caustic solution and the mixture was filtered. Reduction with hydrogen at 180- m C. and 1000 pounds per square inch gave 43 grams of p-cyclohexyl butyric acid. 8. P. 155' C. Nu 1.4632 R. E. 170. The reaction may be repre- 4-H. -e CgHgCHiCHaCOOH In accordance with another feature of the invention, ester-lactones may be prepared by the hydrogenation of the addition products of ketenfl sented as follows: a with furfural. These ester-lactones are valuable c B10003 011F080 plasticizers for molding materials made from cel lulose esters. acetophcmne Ketene Bungle v (flown-0 m o'nuomcmmmcoon Ketene was passed into 300 grams of i'urfu'ral =0 80 containing 0.5 gram anhydrous potassium acetate p-rhsnyl-s-butym until the theoretical increase in weight had taken place, thus indicating the formation of the p-laclmmflc III tone of p-(2-furyl) -,B-hydroxy propionic acid as 250 grams of flirfural containing 0.5 gram of 1111mm! the 110mm! 111mm anhydrous potassium acetate was treated with EH|!H n cn cn ketene while mum H c CH 0 0 H ,CH CH o of so to 0., thereby forming p-(2-furyD-p- F C propiono lactone. when an increase in wiggling-gt I g ff sa ww' 40 This fl-lactone was diluted with 400 grams of reduced t t t 650 C. over m m m dloxane and placed inn stirrer autoclave Distillation gave 140 m of 5 grams of Raney nickel and reduced with bymryl) pmpmmc cm a R n I m drogen. The reduction was conducted in two The reaction a a mum: stages of temperature. 1 The first reduction was conducted at a temperature of 160 C. for 4 hours and the p-lactone was reduced to -(z-tetrahyl 'urinral Kstane drofuryl) -propionic acid which was then further cartoon-o m --o (clmmomcmcoon "411M at tempemm to m =0 fi-(fl-letrabydrdm-yl) t equation.

zeta hydroxy-gamma-heptolactone as shown in pmpionicadd M lH-P wm mc cm 210 0.

As indicated in the above exampleathe simple K )m-CMHOOE E lactones may be hydrosenated as such, or in aco cordance with another feature of the invention. they may be partially polymerized tothe polyestersofp-hydroayacidaandtbenreducedto substituted acids. tion is carried out The zetav hydroxy-gamma-heptolactone reacts as described in U. 8. Patent 2,361,036. p-lactones with the p-(Z-tetrahydrofuryi) -propionic acid to have a tendency to form a dimer which has a 00 yield an ester-lactoneasshownintheequation.

greater heat stability than the simple lactone. This example presents a new method for forming The dimer and higher polymers have the advan 10 this ester-lactone which is described and claimed tage over the simple lactone in that the reducin Hasche and Gordon Patent 2,364,358 of Detion takes place readily at lowertemperatures and cember 5, 1944.

pressures. This fact permits the preparation of These examples illustrate preferred conditions aryl substituted aliphatic acids in accordance with a for making substituted aliphatic carboxylic acids my invention as shown in the following example. by the reduction of the p-lactones obtained from any? aromatic aldehydes and aromatic ketones, and polymers of such p-lactones. It will be understood that a relatively large number of such acids can be produced in a like manner from comparable lactones and ester-lactones. In general, the reaction can be carried out at a temperature between 90-240 C. although the preferred ranges are: for simple lactones, 130-190 C.; for dimers and/or polymers, 90-190 C.; and ester lactones, 210230 C. Pressures up to 150 atmospheres are desirable. Higher pressures may be used, but there appears no substantial advantage in employing such higher pressures. The hydrogenation may be carried out in the presence of inert diluents such as dioxane, cyclohexane, and heptane.

with lactones containing furfural and derivatives thereof a diluent is preferably employed to aid in controlling the rate of the reaction.

The Raney nickel catalyst employed in thereduction of the p-lactones described herein may be prepared as shown in U. S. Patents 1,628,190 and 1,915,473 by a method of leaching out aluminum from a nickel-aluminum alloy with sodium hydroxide. While Raney nickel is the preferred catalyst, other suitable hydrogenation catalysts may be used such as nickel on kieselguhr.

I claim:

1. The process for preparing substituted aliphatic carboxylic acids which comprises hydrogenating in a closed vessel in the presence of a Raney nickel hydrogenation catalyst at a temperature within the range of 90 C. to 240 C. and at a pressure within the range of 100 to 2000 pounds per square inch the p-lactones having the general formula:

wherein R is a phenyl group, and R. represents a member selected from the class consisting of a hydrogen atom and a methyl group, and n represents a small whole number from 1 to 4.

2. The process for preparing ,B-cyclohexyl propionic acid which comprises hydrogenating p-phenyl-p-propiono lactone in a closed vessel at a pressure of approximately 700 pounds per square inch and a temperature of approximately 180 C. and in the presence of a Raney nickel hydrogenation catalyst.

3. The process for preparing ,B-cyclohexyl butyric acid which comprises hydrogenating fl-phenyl-fl-butyro lactone in a closed vessel at a pressure of approximately 700 pounds per square inch and a temperature of approximately 180 C. and in the presence of a Raney nickel hydrogenation catalyst.

HUGH J. HAGEMEYER, Ja.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Adkins, "Reactions of Hydrogen, U. of Wisconsin Press, 1937, page 78.

Boese, Diketene, Article in Ind. 8; Eng. Chem., January 1940, me 20. 

